Donald Eugene Harding was born on March 1, 1949, in a small house in Goodrich, Arkansas. By the time a doctor arrived to assist with his birth, Harding was struggling to breathe, which led to him suffering from organic brain syndrome. He also had neonatal jaundice. Harding's father was an alcoholic who left the family when Donald was young. This abandonment affected Donald, his older brother Darryl, and their mother, Maycle.

As a toddler, Harding was sent to the Child Guidance Clinic in Little Rock, Arkansas. A doctor there wrote a report stating that Maycle was "very immature and narcissistic" and not fit to care for her sons. Eventually, Harding's mother remarried a man named Fred Brown. Fred was ill with tuberculosis, and the family moved to a sanatorium for treatment. Harding claimed that the staff at the sanatorium mistreated him. He alleged that one nurse punished him by dunking his face in a toilet after he wet his bed.

After about two years in the sanatorium, Harding's family left. He then moved back and forth between living with his mother and his grandparents. Ultimately, he settled in a poor area of North Little Rock with his mother. During his childhood, he witnessed physical abuse when Fred Brown beat Maycle. In school, Harding had serious behavioral issues, including defiance and skipping school.

In February 1960, when Harding was almost eleven years old, a doctor reported that he had shown signs of suicidal behavior at the age of nine. He had slashed his wrists and left a note threatening to jump in a river. The same doctor noted that while his brother did not have similar issues, Donald had expressed a desire to kill. The doctor linked Harding’s behavior problems to his brain damage. Maycle also mentioned that Harding’s issues worsened after he fell from a crib and was hit by a swing.

During his preteen and teenage years, Harding underwent three EEGs, with the last one in 1968. These tests confirmed he suffered from organic brain damage and had epileptic seizures. At the age of 11, he was arrested for joyriding. This led to a few years of being sent to different institutions for troubled youth, including the Arkansas Boys' Industrial School and the Arkansas State Hospital.

On December 4, 1964, when Harding was 15, he was convicted of four counts of burglary and three counts of grand larceny. Although his sentence was initially suspended, he escaped from the Boys' Industrial School and committed another burglary. This resulted in his sentence being revoked, and he was sent to an adult maximum security prison called the Tucker Unit to serve a 15-year sentence.

While in prison, Harding faced more trouble. In 1970, he was convicted of attempting to escape. During his time in prison, he attempted suicide again. He was released in 1973 but soon got into more legal trouble. Harding was convicted in federal court for conspiracy to commit an offense against the United States and served another five years in prison.

On December 10, 1979, Donald Harding committed a robbery and murder in Dallas, Texas. He killed 27-year-old Stanton Winston Blanton in his apartment. On December 18 Harding stole a vehicle and identification from Ronald Svetgoff, documents he used repeatedly to conceal his identity as he traveled and committed further robberies. After this, he traveled to California, where he continued his crime spree.

On January 3, 1980, in South Lake Tahoe, California, he entered the hotel room of Charles Dickerson, a 35-year-old man. Harding robbed Dickerson and left him bound and gagged. Dickerson was later found dead due to suffocation caused by the gag.

Harding then took the life of Gerald Huth on January 10, 1980. Harding shot Huth after he stopped to help him on the highway. Huth's body was discovered later, hidden in a field.

After these murders, Harding moved to Arizona. On January 24, 1980, he entered the hotel room of Allen F. Gage, a 38-year-old doctor. Harding bound Gage and gagged him, leading to Gage’s suffocation.

The next day, Harding posed as a security guard to enter a motel room in Tucson, Arizona. Inside, he found businessman Robert Wise and his colleague Martin Concannon. Harding restrained both men, assaulted Wise with a lamp, and ultimately shot them. Their bodies were discovered the following day.

Harding's violent spree ended when he was arrested on January 25, 1980. Authorities found him with a stolen gun and false identification. He faced multiple charges across several states, including five murders. In October 1980 he assaulted a fellow inmate and later was convicted for that jail assault (conviction returned July 30, 1981), a fact prosecutors later cited as an aggravating circumstance. In February of the following year he attacked jail guards and attempted to stab one, further underscoring the violence that surrounded him in custody.

Harding’s murder trial for the Tucson killings began April 21, 1982. The proceedings were tense and heavily secured; sheriff’s deputies masked the first rows of the courtroom to prevent hostage‑taking attempts and testified to Harding’s threats against participants. Harding frequently represented himself or mounted a partial self‑defense by resting on claims related to his organic brain damage. His lawyers emphasized the neurological testing and the long institutional history that, they argued, impaired his impulse control.

On April 27, 1982, after roughly five hours of jury deliberation, Harding was found guilty of two counts of first‑degree murder in the Tucson slayings and of related robberies and kidnappings. At sentencing the court found several aggravating factors and imposed the death penalty for the double murder. He was also given consecutive lengthy prison sentences for the robberies and the theft of Concannon’s vehicle. Subsequently, Harding received a third death sentence for the murder of Allen Gage in Phoenix. After multiple appeals and post‑conviction proceedings that upheld his convictions and sentences, his execution moved forward.

Harding spent nearly a decade on Arizona’s death row. His legal team continued to press claims about his mental and neurological deficits, seeking clemency without success. At a parole and pardon board hearing the panel declined to recommend clemency to the governor. Public response to Harding’s impending execution included protests by anti‑death‑penalty activists, while families of victims and state officials pressed for finality.

The execution, carried out shortly after midnight on April 6, 1992, proved especially controversial. Harding was executed by lethal release of hydrocyanic gas in Arizona’s gas chamber; witnesses described an extended and violent dying process that lasted over ten minutes.